PROTOSTEGIDiE. 



*93 



with the upper border of the jugal. The hinder end of the bone is broken away, so that the 

 whole length can not be determined. The breadth of the bone, taken just behind the process 

 mentioned, is 105 mm. 



No other parts of the palatines appear to have been preserved than that already mentioned. 

 No parts of the premaxillae, nor vomer, nor parietals, nor supraoccipital appear to have been 

 obtained with the bones above described. 



Portions of the skull of this species were described by Case as cited in the synonymy. 

 The supraoccipital is stated to resemble closely that of the Cheloniidae, and to be quite different 

 from that of Dermochelys. The basioccipital resembles that of the latter species, except that 

 the portion belonging in the condyle is well ossified. The basisphenoid is said to resemble that 

 of Dermochelys, but is not so large. Case pointed out that the hinder end of the pterygoid was, 

 as in Dermochelys, separated from the exoccipital by a lateral process of the basioccipital. The 

 imperfectly preserved palatines indicated that the choanae were placed far forward. The vomer 

 had no descending process to assist in underflooring the nasal passages. The quadratojugal 

 and the squamosal were found to be as in the Cope^specimen, but to the present writer it 



isv^ rad 



yu 



pmx. 





Fig. 248. Protostega gigas. Skull, limb bones, and front of carapace. X. 

 No. 1421 Carnegie Museum, Pittsburg. 



Skull, /r, frontal; ju, jugal; mx, maxilla ; nar, nares; orb, border of orbit ; pa, parietal ; prf, prefrontal ; pmx, 



premaxilla: pof, postfrontal; qu, quadrate; qj, quadratojugal; sq, squamosal. 

 Lower jaw. ang, angular; dart, dermarticular, or prearticular; den, dentary; by, hyoid; sur, supraangular. 

 Carapace, nu. p, part of nuchal; per. i, per. i, first and second peripherals; r. 2, second rib. 

 Fore limb, c, centrale; hum, humerus; rad, radius; ul, ulna ; ral?, radiale ? ; /', intermedium ; uln, ulnare; pi, 



pisiforme; 1-5, carpals of second row; I-V, metacarpals. 



appears that Case has mistaken the upper border of the quadratojugal for the lower. The 

 mandible was in perfect condition. The symphysis is represen*ed as being equal to a very little 

 more than one-third the whole length of a ramus. In addition to the bones found in the lower 

 jaw of ordinary turtles Case states that the bone called by Baur the presplenial, by Williston 

 the true splenial, is present. 



The bones described and figured by Cope as metapodials (Cope's plate xii, figs. 3, 4) are 

 certainly not such, but epipodials. The original of his fig. 3 appears to be a tibia. The bone 

 on the right of his fig. 4 may be a radius. The same bone in Archelon, as Wieland informs 

 the writer, is now regarded by him as the ulna. 



No. 1421 of the Carnegie Museum, Pittsburg, was secured in the Niobrara Cretaceous, 

 near Hackberry Creek, Gove County, Kansas. It furnishes the nearly complete skull; the 

 humerus, radius, ulna, most of the carpal bones, and some phalanges of the right flipper; and 

 the nuchal and first three right peripherals. These bones are yet imbedded in the matrix, so 

 that only their upper surfaces are visible. The remains have been studied and described by 

 Wieland, whose figure is here reproduced (fig. 248). The following measurements of the skull 

 are taken from his paper: 



